Ribosomes

• What are ribosomes?


  Small cytoplasmic granules found in all cells.
• Where in a cell might ribosomes occur?


  In the cytoplasm or associated with the RER.
• What are the two types of ribosomes?

  80s and 70s.
• Where are 80s ribosomes found?


  In eukaryotic cells.
• Where are 70s ribosomes found?

  In prokaryotic cells, mitochondria and chloroplasts.
• What size are 80s ribosomes?

  25 nanometres in diameter.
• What size are 70s ribosomes?

  Slightly smaller than 80s.
• What are ribosomes made of?

  One large subunit and one small subunit.
• What does each subunit contain?

  Ribosomal RNA and protein.
• What are ribosomes the site of?

  Protein synthesis.
• What do ribosomes account for and why?

  25% of the dry mass of a cell, as they occur in such vast numbers.